352 HYMENOPTERA OF AMERICA. [PART I. 



abdomine gracili, punctato ; autennis et clypeo omnino atris ; puncto 

 froutali, raacnlis 2 pronoti, teg u lis parti m, post-scutello et abdominis 

 segmentoruui 1', 2' imagine sat late, flavis; tertii fascia flava abbre- 

 viata ; pedibus nigris, tibiis flavis, tarsia fuscis; alis subinfascatis. 



$. — Longit. 9.5 mm. 



Odyn. Huro Sadss. Et. Vespid., Ill, 297, 185, £ (1854). 



Bab. United States. 



148. O. Jloliicanus Sacss. — Minutus, gracilis, punctatns, niger; 



puueto froutali et post-oculari, maculis 2 pronoti, post-scutello abdo- 



minisque segmentorum l 1 , 2' limbo, flavis. Tibiis flavis, tarsis fuscis. 



Alis byalinis venis fuscis. — Longit. S mm. 

 %. Clypeo discoidali, fiavo, subemarginato ; puncto in labro et fascia in 



scapo flavis ; autennis subtus ferrugineis. 



Odyn. Mohicanus Sauss. Et. Vespid., Ill, 297,. 185, % (1854). 



Bab. United States. State of Xew York. 



III. Metathorax not produced superiorly beyond the post-scutel, 

 convex; its hinder face parted by a deep groove. Post- 

 scutel truncate ; having a superior transverse face and 

 a posterior vertical or oblique face ; the two faces separated 

 by a sharp edge. 



Form quite elongate, exactly the same as in the last subdivision 

 {II, 3), 1 very slender, elongate; the abdomen slender, 

 spindle-shaped; its first segment funnel-shaped. Post- 

 scutel always black; scutel often marked with yellow. — 

 Insects small, black, shining, with pale ornaments. 



These insects have much the appearance of those of the group 

 of 0. Totonacus, but the prothorax is marginate anteriorly and 

 the scutel is maculate, not the post-scutel. 



A. Metathorax quite unarmed superiorly. 



149. O. AcolliUUS Sacss. — Parvulus, gracillimus, elongatus, niger, 

 cribrato-punctatus ; pronoto antice cristato-bidentato ; post-scutello 

 truncato, elevato-cristato ; metanoto tenuiter punctato, inermi, bicon- 

 vexo, per sulcum partito ; abdominis primo segmento infundibuliformi, 

 valde punctato, basi paulum petiolato, utrinque subdentato, supra tumido, 

 aiue martrinem transversini subcanaliculato ; secundo paulo depiesso, 

 basi coarctato; reliquis vix punctatis ; pronoto. scutello abdominisque 

 segmeutis 1°, 20, vel 1°, 2°, 4°, flavo-marginatis ; macula subalari 



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